Revert "telemetry: Add GetRendererProcessFromTab to timeline model."

tools/perf/metrics/rendering_stats.py

Index: tools/perf/metrics/rendering_stats.py
diff --git a/tools/perf/metrics/rendering_stats.py b/tools/perf/metrics/rendering_stats.py
index 1114a2f032093e7ca45b3c2bfd709c31bc5b1de4..745cdc98a519694b703288d89a743075d2a37a60 100644
--- a/tools/perf/metrics/rendering_stats.py
+++ b/tools/perf/metrics/rendering_stats.py
@@ -4,9 +4,11 @@
 
 from operator import attrgetter
 
+RENDER_PROCESS_MARKER = 'RenderProcessMarker'
+
 
 class RenderingStats(object):
-  def __init__(self, renderer_process, timeline_markers):
+  def __init__(self, render_process_marker, timeline_markers):
     """
     Utility class for extracting rendering statistics from the timeline (or
     other loggin facilities), and providing them in a common format to classes
@@ -18,8 +20,9 @@ class RenderingStats(object):
 
     All *_time values are measured in milliseconds.
     """
+    assert(len(render_process_marker) == 1)
     assert(len(timeline_markers) > 0)
-    self.renderer_process = renderer_process
+    self.renderer_process = render_process_marker[0].start_thread.parent
 
     self.frame_timestamps = []
     self.frame_times = []